1. Technical Field
The present invention relates to a substrate for an electro-optical device, and an electro-optical device and an electronic apparatus using the substrate for an electro-optical device.
2. Related Art
For example, as the electro-optical device, a liquid crystal device and an organic electroluminescence (EL) device or the like used in a display unit, such as a portable information terminal, a note type personal computer, and the like are known. In the substrate for an electro-optical device used in the electro-optical device, a light shielding film, which is called a black matrix (BM) for partitioning a plurality of pixels, is provided. By providing the light shielding film between pixels, light that leaks from between the pixels is blocked, and thus the reduction of contrast and color mixture are prevented and excellent display is realized.
For example, in JP-A-2001-330821, the electro-optical device including a pair of a first substrate and a second substrate is disclosed. A predetermined pattern is provided in a non-opening region of each pixel of the first substrate, and the light shielding film is provided in a region in which the predetermined pattern is at least partially covered in a case of viewing the predetermined pattern in a plane manner, in the second substrate that is oppositely disposed to the first substrate. The light shielding film is formed by laminating a high reflective film of a first reflection rate and a low reflective film of a second reflection rate lower than the first reflection rate. There is an example that the high reflective film covers the low reflective film. By providing the light shielding film on the second substrate, light incident on the high reflective film from the second substrate side is reflected. With this, it is unlikely for light to be incident on the non-opening region of each pixel. Meanwhile, it is unlikely for light, which is incident on the opening region of each pixel, reflected from the first substrate side, and returned toward the second substrate, to be incident on and reflected from the low reflective film. That is, since internal reflection is reduced between the first substrate and the second substrate which are oppositely disposed, it is possible to suppress the reduction of display quality caused by the internal reflection.
In the electro-optical device of JP-A-2001-330821, the predetermined pattern functions as a pixel switching thin film transistor (TFT), scan lines and data lines connected to the TFT, or the like. In addition, the light shielding film is provided in an island shape so as to overlap at least the TFT in a plane manner, or provided in a stripe shape or a lattice shape so as to overlap the scan lines and the data lines in a plane manner. As an example of the high reflective film constituting the light shielding film, there is an aluminum film including nitrogen compounds and refractory metal, and as an example of the low reflective film, there is a film including chromium oxide. As a method for forming the light shielding film, first, the high reflective film is formed on a substrate, and then patterning is performed on the high reflective film corresponding to the predetermined pattern. Accordingly, a method in which the low reflective film is formed to cover the high reflective film on which the patterning is performed, and patterning is performed on the low reflective film again, is considered. However, when positional accuracy is not sufficiently secured in the patterning of the low reflective film, there is a possibility that it may not reliably cover the high reflective film on which the patterning is performed. In addition, in etching processing of the patterning of the low reflective film, there is a possibility that defects occur by etching a part of the high reflective film. In particular, when the size of a pixel is high definition, since the width of the non-opening region between pixels on which the predetermined pattern is provided also becomes narrower, high positional accuracy is acquired in the patterning of the low reflective film. When a portion of the high reflective film that is not covered by the low reflective film exists, internal reflection in the portion becomes remarkable and then there is a possibility that characteristics of contrast or the like are partially reduced. In addition, when defects occur in a part of the high reflective film at the time of patterning of the low reflective film, there is a possibility that the reliability of the electro-optical device is impaired by diffusing the material of a defective high reflective film.